The present invention relates to a device for cleaning threaded studs and, more particularly, to a device for cleaning such studs in a radioactive or otherwise hazardous environment.
The domed head of a nuclear reactor pressure vessel is normally secured to the vessel body by means of a plurality of very large threaded bolts or studs. These studs can be several feet long and more than six inches in diameter. At scheduled intervals called "outages", the reactor is shut down, so that, a refueling and fuel shuffling operative can be performed and various pieces of equipment, including the studs, can be cleaned and inspected. Due to their size, manual cleaning of the studs is quite cumbersome. More importantly, the studs, and other pressure vessel components, are radioactive and, thus, personnel can only be exposed thereto for short periods of time.
It is, therefore, a primary object of the present invention to provide a device for cleaning threaded studs on a nuclear reactor pressure vessel and, further, to provide such a device by which cleaning of the studs may be effected while minimizing the exposure of personnel to radiation.
The foregoing and other objects and advantages as may hereinafter appear, are accomplished by a device comprising a cylindrical brush holder rotatably carried in a housing. An annular brush, disposed on the inner surface of the brush holder, is adapted to telescopingly engage the threaded portion of a stud. Motor means, preferably an electric motor mounted on the housing, rotates the brush to clean the stud threads. Advantageously, guide means, preferably a frusto-conical member disposed on the lower end of the housing, facilitates lowering the device onto an upstanding stud. Vacuum means may be provided, preferably comprising a vacuum source connected to the housing, to capture particulate matter, much of which is radioactive, dislodged from a stud during cleaning.